激活小鼠ZI区GABA能神经元可促进七氟醚和丙泊酚的麻醉诱导而对麻醉维持及觉醒无影响

Activation of GABAergic neurons in the zona incerta accelerates anesthesia induction with sevoflurane and propofol without affecting anesthesia maintenance or awakening in mice

目的探索未定带区(ZI)γ-氨基丁酸(GABA)能神经元对七氟醚和丙泊酚麻醉-觉醒的调控作用。方法将48只雄性C57BL/6J小鼠分为8组(6只/组)。研究七氟醚麻醉时,化学遗传学实验分为hM3Dq组(注射携带hM3Dq的腺相关病毒)和mCherry组(注射仅携带mCherry的对照病毒);光遗传学实验分为ChR2组(注射携带ChR2的腺相关病毒)和GFP组(注射仅携带GFP的对照病毒),注射剂量均为100 nL。研究丙泊酚麻醉时,化学遗传学实验分为hM3Dq组和mCherry组;光遗传学实验分为ChR2组和GFP组。上述各组处理方法同七氟醚。通过化学遗传学和光遗传学技术激活ZI区GABA能神经元,观察其对七氟醚和丙泊酚的麻醉诱导及觉醒的调节作用,通过脑电监测观察其在七氟醚麻醉维持中的作用。结果在七氟醚麻醉中,与mCherry组比,hM3Dq组麻醉诱导时间显著缩短(P<0.05),与GFP组比,ChR2组麻醉诱导时间显著缩短(P<0.01),而两实验中麻醉觉醒时间差异均无统计学意义。在丙泊酚麻醉中,hM3Dq组比mCherry组麻醉诱导时间显著缩短(P<0.05),ChR2组比GFP组麻醉诱导时间显著缩短(P<0.01),而两实验中麻醉觉醒时间差异均无统计学意义。光遗传激活ZI区GABA能神经元没有改变七氟醚麻醉维持时的脑电频谱。结论ZI区GABA能神经元能够促进七氟醚和丙泊酚的麻醉诱导,而对麻醉维持及觉醒无调节作用。

Objective To explore the regulatory effects of GABAergic neurons in the zona incerta(ZI)on sevoflurane and propofol anesthesia.Methods Forty-eight male C57BL/6J mice divided into 8 groups(n=6)were used in this study.In the study of sevoflurane anesthesia,chemogenetic experiment was performed in 2 groups of mice with injection of either adenoassociated virus carrying hM3Dq(hM3Dq group)or a virus carrying only mCherry(mCherry group).The optogenetic experiment was performed in another two groups of mice injected with an adeno-associated virus carrying ChR2(ChR2 group)or GFP only(GFP group).The same experiments were also performed in mice for studying propofol anesthesia.Chemogenetics or optogenetics were used to induce the activation of GABAergic neurons in the ZI,and their regulatory effects on anesthesia induction and arousal with sevoflurane and propofol were observed;EEG monitoring was used to observe the changes in sevoflurane anesthesia maintenance after activation of the GABAergic neurons.Results In sevoflurane anesthesia,the induction time of anesthesia was significantly shorter in hM3Dq group than in mCherry group(P<0.05),and also shorter in ChR2 group than in GFP group(P<0.01),but no significant difference was found in the awakening time between the two groups in either chemogenetic or optogenetic tests.Similar results were observed in chemogenetic and optogenetic experiments with propofol(P<0.05 or 0.01).Photogenetic activation of the GABAergic neurons in the ZI did not cause significant changes in EEG spectrum during sevoflurane anesthesia maintenance.Conclusion Activation of the GABAergic neurons in the ZI promotes anesthesia induction of sevoflurane and propofol but does not affect anesthesia maintenance or awakening.